[theamk]

Isn't that only for failed commands? so if command succeeds with warnings, or if if fails, but the retries and passed, ghen you get no output.

[yeti-sh]

The exception is raised if the command returns a non-zero error code. If it returns a zero error code then the return value of, say,

    compose.up()

contains the command's stdout.

In addition stdout can be redirected to a file, or to another command, or to a callable, ­— which will be called for chunks of stdout while the command is in operation.